Manufacture of artificial threads



Patented July 5, 1938 UNITED STATES PATENT OFFEQE MANUFACTURE OF ARTIFICIAL THREADS N Drawing. Application June 2, 1936, Serial No. 83,168. In Germany June 8, 1935 Claims.

This invention relates to the manufactureof artificial threads and more particularly to artificial threads containing sulfur and nitrogen.

One of its objects is a process of producing 5 artificial threads from Viscose containing sulfur and nitrogen. Another object are the threads obtained by this process. Further objects will be seen from the detailed specification following hereafter.

Several processes have been described for making cellulose artificial threads containing nitro gen and sulfur and having afiinity for acid wooldyestufis. Such processes, however, meet with several difiiculties if the nitrogeneous derivative is to be produced in the form of a spun fiber and these have hitherto prevented a large scale application of the processes. The difficulties are due on the one hand to the fact that the processes must be conducted under conditions which damage the sensitive spinning fiber and on the other hand the conversion product of the Xanthate solution cannot be spun because it is not suitable for technical spinning.

This invention relates to a process of making artificial fibers from derivatives of cellulose containing nitrogen and sulfur by first spinning the ordinary viscose by means of a usual spinning bath to produce threads containing cellulosfe Xanthate and then treating the threads, either directly or, if desired, after purification in a second bath which may consist, for example, of a neutral or feebly acid salt solution, with ethyleneimine or a homologue thereof which reacts analogously to the said imine or homologue or another cyclic nitrogeneous base or a salt of any of these. Such imines are besides ethyleneimine and its products of substitution such as ethyleneimine-Z-carboxylic acid, ethylene-imine sulfonic acid, furthermore C-alkyl-, acyl-, cycloalkyl-, aryl-, or aralkyl products of substitution such as N-methylethylene-imine, 2-3-diacetylethyleneimine, 2-octadecyl-ethylene-imine, N-cyclohexanolethylene-imine, 2-phenylethylene-imine, N-

propyl-2-vinyl-ethylene-imine and analogous products of substitution. These cyclic imines have the character that they react very rapidly and completely with the Xanthate groups of the fibers so that this mode of treatment may be applied in the continuous spinning process, which is not possible in the case of the known process'es. The use of these substances introduces nitrogen and sulfur into the fibers by such a gentle operation that the fibers cannot be damaged. The process consists in the application of a reaction of addition which leads, without formation of elimination products, to what may be called mercaptothiazolidinewellulose ethers. These mercaptothiazolidine cellulose ethers may be assumed to have the following formula s11 NH-OH2 R representing the radical of cellulose.

Any ripened or unripened viscose may be spun by this process in the usual apparatus. It is only essential that the fiber which is to be treated by the invention should contain sufiicient free Xanthate-groups. The more Xanthate groups that such a fiber contains the higher can be the nitro gen and sulfur content of the final product. By using the grades of sulfidizing of unripened viscose usual in the artificial viscose silk industry fibers containing 3 per cent of nitrogen can easily be obtained. When the sulfidizing is higher, products correspondingly richer in nitrogen are obtained. For a quantitative, or at least approximately quantitative, reaction of all the Xanthate groups present in the fiber a subsequent acid decomposing-bath is not necessary. It is, however, advantageous not to cause all the Xanthate groups to react and this can be secured by suitably adjusting the dose of the imine substance used. Xanthate groups which still remain may be split off by subsequent reaction in an acid bath.

The cyclic nitrogeneous base may be applied in the form of vapour or liquid or dissolved in water or another solvent. It has been found that both the free bases and their salts can react with the Xanthate groups so that, for example, basic, neutral or acid solutions of the bases may be used as the reaction bath.

Artificial fibers produced by this invention from cellulose derivatives containing nitrogen and sulfur have properties similar tothose of wool. In particular they can be dyed in admixture with wool with the usual wool-dyestufis in the same degree of fastness. The tensile strength and extension of the new artificial fibers do not fall behind those normal for cellulose artificial fibers.

The following examples illustrate the invention:

Example 1.-Normal viscose, ripe for spinning and containing about 25 Xanthate-groups per C6 molecules of cellulose, is spun in a bath containing a 32 per cent solution of sodium sulfate and 4.2 per cent of sulfuric acid at a temperature of 35 C. to produce a bundle of Xanthate threads; this bundle is then treated in a washing bath consisting of a 30 per cent solution of sodium sulfate at 50 C. The bundle of thread is now squeezed and passed in this condition through a chamber at 50-60 C. in which ethylene-imine vapour is circulating, whereby the reaction of the xanthate groups contained in the coagulated bundle of threads with the ethyleneimine is completed in a few seconds. The bundle of threads is then washed in a bath of 5 per cent of sulfuric acid, washed with water and revived. The dried threads contain 1-1.2 per cent of nitrogen and can be dyed with acid wool-dyestuffs.

Example 2.Viscose having about 50 xanthategroups per 100 cellulose Cir-molecules is spun by any usual method to a xanthate thread and the bundle ofthreads is passed through an aqueous solution of percent strength of Nmethylethyleneimine, which is feebly acid with sulfuric acid and may be mixed with an inorganic salt. During the gradual complete winding of the spool or the reel on which the bundle of thread is taken up the N-methylethylene-imine has time to react with the xanthate groups. The fibrous material thus obtained has an afiinity to wool-dyestufis and a nitrogen content of 2.8 per cent.

Example 3.-Viscose having 45 xanthate groups per 100 Cs-cellulose molecules is spun in known manner to xanthate threads and the bundle of threads is passed through a gutter into which, through two tubes, an aqueous solution of acetic acid is led on the one hand'and on the other hand an aqueous solution of ethylene-imine is fed in gradual flow to the-amount of grams of ethylene-imine and 30 grams of acetic acid per 100 grams of cellulose passed. Finally the bundle of threads is passed through a room heated to 75 C. in which it remains for 10 seconds. After a final bath containing 3 per cent of sulfuric acid in which, if desired, undecomposed residual xanthate groups are eliminated, the bundle of threads is led through a rinsing or soaking bath and is dried. The fibers contain 2.5 per cent of nitrogen and 10-11 per cent of sulfur; they have good substantivity to wooldyestuffs,

Example 4.--Viscose containing about 25 xanthate-groups per 100 Cs molecules of cellulose is coagulated in a bath containing 30 per cent of sodium sulfate and 2 per cent of sulfuric acid at a temperature of 60 C. The length of immersion of the thread in the bath is 15 cm. and the speed of draft 40 ms. per minute. The thread contains free xanthate-groups and is washed following the spinning process in a bath consisting of a per cent solution of sodium sulfate and then through a bath of a 20' per cent aqueous solution of ethylene-imine. Then the bundle of threads is passed through a chamber heated at 60 C. in which it remains about 15 seconds. The dried fibers contain 1.8 per cent of nitrogen and 4.5 per cent of sulfur.

What I claim is:

1. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose into a precipitating bath containing at most 4.2 per cent of acid to form threads consisting of cellulose xanthogenate and reacting on the formed threads with a cyclic ethyleneimine.

2. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose into a precipitating bath containing at most 4.2 per cent ofacid to form threads consisting of cellulose xanthogenate and reacting on the formed threads with a cyclic ethyleneimine in gaseous condition.

3. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose into a precipitating bath containing at most 4.2 per cent of acid to form threads consisting of cellulose xanthogenate and reacting on the formed threads with a cyclic ethyleneimine in liquid condition.

4. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose into a precipitating bath containing at most 4.2 per cent of acid to form threads consisting of cellulose xanthogenate and reacting on the formed threads with a cyclic ethyleneimine dissolved in a solvent.

5. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose into a precipitating bath containing at most 4.2 per cent of acid to form threads consisting of cellulose xanthogenate and reacting on the formed threads with an imine selected from the group consisting of ethyleneimine, ethylene-imine-2-carboxylic acid, ethylene-imine-sulfonic acid, N-methyl-ethyleneimine, 2-3-diacetyl-ethylene-imine, Z-octadecylethylene-imine, N-cyclohexanolethylene-imine, Z-phenylethylene-imine and N-propy1-2-vinylethylene-imine.

6. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning a viscose containing about xanthate groups per 100 Cs molecules of cellulose into a precipitating bath containing a 32 per cent solution of sodium sulfate and 4.2 per cent of sulfuric acid at a temperature of 35 C. to produce a bundle of xanthate threads, washing the bundle of threads in a bath consisting of a per cent solution of sodium sulfate at 50 C., squeezing the bundle of threads, passing the bundle of threads through a chamber in which ethyleneimine vapour is circulated at -60' C'. and washing the threads thus treated-in a bath of 5 per cent of sulfuric acid.

'7. A process of producing artificial threads con- I taining nitrogen and sulfur which comprises spinning a viscose containing about 50 xanthate groups per 100 cellulose Ce molecules to a xanthate thread and passing the bundle of threads which is formed through an aqueous solution of 10 per cent strength of N-methylethylene-imine which is feebly acid with sulfuric acid,.and winding the threads on a collecting device.

8. A process of producing artificial threads containing nitrogen and sulfur which comprises spinning viscose containing about 25 xanthate groups per 100 C6 molecules of cellulose in a precipitating bath containing 30 per cent of sodium sulfate and 2 per cent of sulfuric acid at a temperature of C. with an immersion length of 15 cm. and at a. speed of draft of 40 ms. per minute, washing the coagulated threads in a bath consisting of a 20 per cent solution of sodium sulfate, passing the bundle of threads through a bath containing a 20 per cent aqueous solution of ethylene-imine, and guiding the bundle of threads through a chamber heated at 60 C. to remain in said chamber for about 15 seconds.

9. Artificial threads consisting of a mercaptothiazolidine cellulose ether.

10. Artificial threads comprising a mercaptothiazolidine cellulose ether.

WALTER MAIER. 

